Testing device



March 21, 1933. v LA 1,902,307

TESTING DEVICE Filed July '16: 1928 l7 I I E q 7 FRED VLARKIN-) abtozmqPatented Mar. 21,. 1933 PATENT OFFICE FRED V. LABKIN, F BETHLEHEM,PENNSYLVANIA TESTING, DEVICE Application filed July 16,

This invention relates to testing devices and more particularly todevices for testing. motor vehicles such as automobiles.

It has for one of its objects to provide simple, compact and safe meansfor testlng a vehicle and its prime mover under actual runningconditions without, movementof the vehicle as a whole.

Another object of the invention is to provide a testing device adaptedto furnish a running test of a stationary vehicle, and of the variouselements of the vehicle such as the engine, transmission, brakes, tires,suspension, etc. p

Another object of the invention is to provide means whereby a vehiclemay be operated under any desired load and at any desired speed withinits range without movement relative to the earth, for purposes ofobservation and testing.

Another object of the invention is to provide means to determine thedraw bar pull and the coefficient of traction of a vehicle at variousspeeds and loads, and to determine the wearing properties of tires, andof various road surfaces.

Other objects of the invention will appear from the followingdescription taken in connection with the drawing which forms apart ofthis specification, and in which:

Fig. 1 is a view in side elevation, partially in section and partiallybroken away, of a testing device embodying this invention;

Fig. 2 is a view in transverse section, substantially on the line 22 ofFig. 1;

Fig. 3 is a view in transverse section substantially on the line 33 ofFig. 1;

Fig. 4 is a view similar to Fig. 2, showing amodified form of the powermeasuring 40 devices and the connecting gearing, and

Fig. 5 is an enlarged section through one of the supporting ringsshowing one way in which the track liners may be secured to these rings.

The former method for testing motor-vehicles by runningthem on thepublic highways has now become dangerous and impractical, especially atthe higher speeds of which modern vehicles are capable, and thenecessity for the testing of vehicles has led to the motor vehicles bymounting them on a fixture,

1928. Serial No. 292,958.

construction of private testing grounds or tracks, which are banked topermit high speeds and are sometimes provided with artificial hills orother devices to provide loads forthe'vehicles. Such testing grounds,however, are very expensive in construction and require a large space,so that it is ordinarily not possible to provide such facilities withinconvenient distance. of the factory or shops in which the vehicles to betested are made or repaired. Such testing methods are also inconvenientwhen used for endurance testing, or testing vehicles and their parts todestruction, because frequent stops must be made in the test forreplenishment of supplies, such as fuel and lubricants, and to makeobservations of the conditions of the vehicle and the progress of thetest.

It has been heretofore proposed to test the wheels resting upon spacedfriction rollers or drums to permit running operation withouttranslatory movement over the ground. The present invention constitutesan improvement in devices of this nature, the advantages of which willsubsequently appear. I

In the accompanying drawing-is shown a device for testing a motorvehicle such as indicated generally at 10, having a foundation adaptedto support a frame 11, and provided with a depressed portion or pit 12.Within the pit 12 are spaced supports 13, shown in the presentembodiment as posts, which are arranged in pairs and provided with pairsof aligned bearings 14, in which transverse supporting axles 15 arejournaled. Each of these axles 15 is provided with a pair of spacedguiding and supporting rollers 16, 9o rigidly secured to the axle 15,which rollers are adapted to support a pair of rings 17 of considerablediameter, arranged in parallel vertical planes to form a circular track18, adapted to rotate on the rollers about a hori- 95. zontal axis. Itwill be understood that the rings 17 are axially spaced a distancecorresponding to the tread of the vehicles to be tested, so that theright hand wheels of the vehicle are supported on one of the rings andthe left handwheels on the other, as clearly shown in the drawin Each ofthe rings 1% is preferably of channel shape in cross section, havingradially I disposed flanges 19 acting as guides to prevent the vehiclewheels from leaving the track. Each ring is also provided with acircumferential rib 20 adapted to seat in a circular groove 21 on therollers 16, whereby the rings are guided, these ribs also considerablystrengthening the rings. The rings are also guided by suitable rollers22, carried by the frame 11 at the top and sides thereof, and providedwith grooves 23 cooperating with the ribs 20.

' Each of the rings 17 is also provided with a circumferential rack 24,the teeth of which are adapted to mesh with the corresponding teeth of apair 'of spurgears 26, rotatably mountedin suitable bearings 27 on asupport 28 in the pit 12, these gears being keyed or otherwise rigidlyconnected to the shaft 29 of a suitable dynamometer or power measuringdevice 31.

The dynamometer is indicatedin the drawing'as being of thedynamo-electric type, and comprises a dynamo-electric machine which mayoperate either as a generator or as a motor. It is to be understood thatthis machine may be connected at will to a suitable source of electricalenergy for operation as a motor, or to a suitable variable resistanceadapted to absorb the output of the machine when operating'as agenerator, and is provided with suitable indicating instruments, such asshown conventionally in Figs. 2 and 4, to measure the power input oroutput of the machine as the case may be. As dynamometers of this natureare well konwn in the art to which this invention relates, the specificconstruction thereof, and the circuits, controls and instrumentsconnected thereto, have not been illustrated, but it is to be understoodthat any other suitable power measuring device, with means for imposinga braking load upon the track 18, may be used if desired. V

The vehicle 10 is restrained from movement as a whole with respect tothe frame 12, or the ground, by'means of a draw bar or tension member 32of any suitable construction which may be removably clamped to thevehicle, preferably to the frame thereof, and is connected at its otherend to an-anchor or post 33 fixed in' the foundation of the device.Between the draw bar 32 and the anchor 33 is interposed suitable meansfor measuring the pull exerted bythe vehicle on the anchor. This meansmay be of any desired construction, but it has been diagrammaticallyillustrated in the drawing as comprising a bell crank member 34fulcrumed on the anchor .33 and havingone arm connected to the drawsecured to the foundation. This device con- 2 a test of the wearingqualities of such mate-' rials as well as the wear of vehicle tires. Theliners may also be formed with depressions and raised portions, as shownin Fig. 5, irregularly spaced to simulate bumps, holes and otherobstructions such as are encountered in the actual driving of a vehicle,thus affording a running test which closely approxlmates actual drivingconditions.

The operation of the device will be easily understood from the foregoingdescription. The vehicle to be tested is placed in position in the track18 in any convenient manner, the vehicle wheels contacting the tractionsurfacesof the liners 38 and the draw bar 32 is connected to the vehicleto prevent movement thereof. In this position the vehicle is started,and this may be accomplished either by the usual engine startingmechanism built into the vehicle, or by cranking it through rotation ofthetrack 18 by means of the dyhlcle power output being measured by thepower output of the dynamometer 31, operating in this instance as agenerator, plus'the work done on the draw bar spring, as indicated onthe scale 37. i The vehicle engine may be heavily loaded as in theascension of a steep hill by increasing the electrical load on thedynamometer 31, thus resisting rotation of the track 18 through theconnecting gearing 26 and 24. On the other hand the dynamometer may beoperated as a motor and positively drive the track 18 at'a speed greaterthan the speed of the vehicle 10 thus reproducing the conditionsobtained when the vehicle is coasting down a hill. I

As the vehicle does not move from its geographical position in thetesting device, fuel, lubricating oil, water and all other necessarysupplies may be readily provided while the test is in progress, so thatit is convenient to drive a vehicle to destruction in this mannerwithout stopping the test if desired. .Furthermore, any desired unit ofthe vehicle may be tested. For example, the track 18 maybe driven by thedynamometer, operating as. a motor, and its rotation resisted by meansof the vehicle brakes, thus providing a comprehensive test of thesebrakes under all possible conditions. Such phenomena as the well knownshimmy may be reproduced at will, and may be closely observed even whilethe vehicle is being operated at high speeds.

In Fig. 4 is shown a form of the invention having a differentarrangement of power measuring means. In this device each of thecircular racks 24 of the track rings 17 is connected to .an independentdynamometer 41 through se arate spur gears 42, these gears being suitaly mounted as in the bearings 43. The electrical connections and thecontrol means of these dynamometers are such that they may be operatedeither independently or together. In this way a convenient means isprovided whereby the transmission mechanism of the vehicle 10, andparticularly the differential gearing thereof, may be tested. By loadinthe dynamometers 41 different amounts, 51c relative speed of the rings17- may be considerably varied, or they may be made to rotate inopposite directions, thus producing any desired operation of the vehicletransmission and its final drive gearing. 7 It will alsobe seen that thetrack 18in the device of thisinvention may be constructed of any desireddiameter within thelimit of the available head room in the building inwhich it is installed. It may therefore have .a large radius ofcurvature so that the segment which the vehicle contacts may be quiteflat, and thus more nearly produce the effect of an actual roadway. Thisis not possible of attainment in testing machines of the traction rollertype, in which the radius of the rollers cannot exceed half the wheelbase of the vehicle without interference.

The present invention is also much safer in operation, especially in thehigh speed testing of vehicles. In the event of a failure of the drawbar or its connections, or other inadvertent disconnection of thevehicle from its anchorage, the vehicleis confined to the track andimmediately upon disconnection begins to climb a steep grade which ismoving in the reverse direction. The device, therefore, not onlyrestrains the vehicle to a closed ath, but rapidl reduces its velocity.

Furt ermore. it will e seen that the device I occupies a relativelysmall amount of floor space, and it may be set up to extend throughseveral floors of a building, for example against one of the side wallsthereof, and may thus be installed in spaces which cannot be utilizedfor any other purpose.

It will be understood that various formsof the invention other thanthose described above may be used without departing from the spirit orscope of the invention.

Having thus described the invention, what 1 is claimed and desired to besecured by Letters Patent, is:

1. In a device for. testing motor vehicles,

a rotatable circular track comprising axially spaced rings having innersurfaces to support the vehicle wheels and having flanges to retain saidwheels, a circumferential guide rib' on each ring, grooved rollers coocrating with said ribs to guide and support t erings, circumferentialracks on said rings, power measuring means, and gearing connecting saidmeans to the racks. H

2. A device for testing motor vehicles comprising a circular trackdrivenby the vehicle and including a pair of axially spaced rings to supportthe vehicle wheels, rollers to rotatably support said rings, guide meansfor the rings associated with the rollers, gear teeth forming acircumferential rack on each of the rings, gears meshing with said gearjan interior diameter large enough to simultaneously receive a front anda rear wheel of an automobile of normal size, means to support saidcircular track for rotation, means to prevent. substantial bodilydisplacement of the vehicle, and means to measure the powertransmittedbetween said track and vehicle.

5. In a device fortesting motor vehicles the combination of a circulartrack having an interior diameter large enough to simultaneously receivea front and a rear wheel of an automobile of normal size, means tosupport said circular track for rotation, and means mounted separatefrom said track and connected thereto for measuring the powertransmitted betvween'said track and Yvehicle.

6. A device for testing motor vehicles the combination of a circulartrack having an interior traction surface large enough to simultaneouslysupport a front and a rear wheel of an automobile of normal size, meansfor circumferentially supporting said track for rotation, and means formeasuring the power transmitted between said track and vehicle.

7. In a device for testing motor vehicles, the combination of twocircular tracks of a diameter larger than an automobile of normal size,means for supporting said tracks 1 for rotation about a common axis,said tracks tracks, and means adapted .to be inounted in a stationaryposition and connected to said N mal size, means for supporting saidtracks one of said tracks and the wheels on the other side of the samevehicle may simultaneously tracks and arranged to;rmeasure the powertransmitted between said tracks and vehicle.

8. In a device for testing motor vehicles, the combination of twocircular tracks ofa diameter larger than an automobile of norforrotation about a common axis, said tracks being spaced apart so that thewheels on one side of a vehicle may rest on the interior of one of saidtracks and the wheels on the other side of the same vehicle may rest onthe interior of the other of said tracks, gear- I ing' interconnectingsaid tracks, and means adapted to be mounted in a stationary positionand connected to said tracks and arranged to measure the powertransmitted between said tracks and vehicle 9. In a device for testingmotor vehicles,

the combination of two circular tracks of a" diameter larger than anautomobile of normal size, means for supporting said tracks for rotationabout a common axis, said tracksbeing spaced apart sothat the wheels onone side of a vehicle may rest on the interior of rest on the interiorof the other of said tracks, and two separate power measuring devicesmounted in a stationar position adjacent said tracks and separate yconnected to said tracks to thereby independently measure the powertransmitted between the wheels of the vehicle and the respective tracks.a

In testimony whereof I afiix my signature.

' FRED V. LARKIN.

